- A rabid dog.
- (figuratively, by extension) Someone who is aggressive and fanatical; an aggressor who cannot be reasoned with.
- 1843, Hernán Cortés, translated by George Folsom, Letters and Dispatches of Cortés:
- Although the enemy saw that they were being hurt, they were such mad dogs that we could by no means prevent their pursuing us
- 1996, Evan Thomas, The Very Best Men: Four Who Dared: The Early Years of the CIA, page 232-233:
- But in 1992, Bissell still maintained, "Lumumba and Sukarno were two of the worst people in public life I've ever heard of. They were mad dogs. Castro I saw not as a mad dog but as a purposeful antagonist. I believed that they were dangerous to the United States. There was a widespread belief that societies in the noncommunist world were exceedingly fragile, susceptible to being destroyed by these demagogues."
- 2007, Henry Van Dyke, The Valley of Vision, →ISBN, page 96:
- We went gladly, without fear or holding back. We were resolute that those mad dogs should not get through. 'They shall not pass'! And they did not pass!" "Glorious!" cried the priest, drinking the story in.
- 2009, Alan Filreis, Counter-revolution of the Word, →ISBN:
- Even their “soft tones” infuriated Bogan: “Stop the mad dogs of Fascism,” these young communists mildly offered, “help our boys dodging Franco's bombs.”